(1) Field of the Invention
The present invention relates to an aluminum composite material and a method of producing the same; wherein lubricative granules are provided at least on a base material surface of an aluminum alloy base material.
(2) Description of the Background Art
An aluminum alloy has been optimally used in devices including such as automobiles, electric appliances, electronic parts, and precious measurement equipment because of its lightness and malleability. Nevertheless, the application of the aluminum alloy is limited to a sliding portion of structures because of low resistance to abrasion. Accordingly, various composite materials such as graphite and activated charcoal with superior lubricating property have been added to a base surface to promote resistance to abrasion.
A composition in which an activated charcoal and ceramics such as alumina particles and alumina fiber are dispersed in an aluminum alloy material was disclosed in Japanese Laid Open Patent Publication No. S58-81.948. Further, a method of manufacturing the composite material was disclosed in Japanese Laid Open Patent Publication No. H6-240305 in which a compact, which was obtained by dehydration or de-alcoholization after alumina short fiber and graphite were mixed with water or alcohol, and an aluminum alloy were made into a complex.
The aluminum composite material as produced above is generally cut mechanically in accordance with the type of application. By the mechanical processing, the lubricative granules exposed on the surface of the aluminum composite material are grinded off. Accordingly, when such an aluminum composite material is used as a sliding member, the lubricative granules are not exposed on the surface or only a very small amount exists, and accordingly, an initial sliding ability or sliding property at a low surface pressure could not be adequately utilized. Accordingly, the aluminum composite materials disclosed in the above JP58-81948 or JP6-240305 could not utilize a desired sliding property even as a sliding member of a specific structure produced by a simple machinery process.